Re: [PATCH] staging: media: lirc: lirc_zilog: Fix for possible null pointer dereference

From: Valdis.Kletnieks@vt.edu
To: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Cc: Jarod Wilson <jarod@wilsonet.com>,
	Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Aya Mahfouz <mahfouz.saif.elyazal@gmail.com>,
	Gulsah Kose <gulsah.1004@gmail.com>,
	Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>,
	Martin Kaiser <martin@kaiser.cx>,
	linux-media@vger.kernel.org, devel@driverdev.osuosl.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] staging: media: lirc: lirc_zilog: Fix for possible null pointer dereference
Date: Thu, 29 Jan 2015 17:12:40 -0500	[thread overview]
Message-ID: <21497.1422569560@turing-police.cc.vt.edu> (raw)
In-Reply-To: Your message of "Thu, 29 Jan 2015 19:48:08 +0100." <1422557288-3617-1-git-send-email-rickard_strandqvist@spectrumdigital.se>

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On Thu, 29 Jan 2015 19:48:08 +0100, Rickard Strandqvist said:
> Fix a possible null pointer dereference, there is
> otherwise a risk of a possible null pointer dereference.
>
> This was found using a static code analysis program called cppcheck
>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
> ---
>  drivers/staging/media/lirc/lirc_zilog.c |    4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)

>  	/* find our IR struct */
>  	struct IR *ir = filep->private_data;
>
> -	if (ir == NULL) {
> -		dev_err(ir->l.dev, "close: no private_data attached to the file!\n");

Yes, the dev_err() call is an obvious thinko.

However, I'm not sure whether removing it entirely is right either.  If
there *should* be a struct IR * passed there, maybe some other printk()
should be issued, or even a WARN_ON(!ir), or something?

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